Robin's Pincushion
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''Diplolepis rosae'' is a
gall wasp Gall wasps, also traditionally called gallflies, are hymenopterans of the family Cynipidae in the wasp superfamily Cynipoidea. Their common name comes from the galls they induce on plants for larval development. About 1,300 species of this gene ...
which causes a
gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...
known as the rose bedeguar gall, bedeguar gall wasp, Robin's pincushion, mossy rose gall, or simply moss gall.Darlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 133 - 135. The gall develops as a chemically induced distortion of an unopened leaf axillary or terminal bud, mostly on field rose ('' Rosa arvensis'') or dog rose (''
Rosa canina ''Rosa canina'', the dog rose, is a variable climbing, wild rose species native to Europe, northwest Africa, and western Asia. Description The dog rose is a deciduous shrub normally ranging in height from , though it can scramble higher into the ...
'') shrubs. The female wasp lays up to 60 eggs within each leaf bud using her
ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...
. The grubs develop within the gall, and the wasps emerge in spring; the wasp is
parthenogenetic Parthenogenesis (; from the Greek + ) is a natural form of asexual reproduction in which the embryo develops directly from an egg without need for fertilization. In animals, parthenogenesis means the development of an embryo from an unfertiliz ...
with fewer than one percent being males. A similar gall is caused by '' Diplolepis mayri'', but this is much less common.


Names

Being so prominent and interesting in appearance, this gall has more folklore attached to it than most. The term 'Bedeguar, Bedegar or Bedequar' comes from a French word, ''bédégar'', and is ultimately from the
Persian Persian may refer to: * People and things from Iran, historically called ''Persia'' in the English language ** Persians, the majority ethnic group in Iran, not to be conflated with the Iranic peoples ** Persian language, an Iranian language of the ...
, ''bād-āwar'', meaning 'wind-brought'. Robin in Robin's pincushion refers to the woodland sprite of English folklore,
Robin Goodfellow In English folklore, The Puck (), also known as Goodfellows, are demon, demons or fairy, fairies which can be Household deity, domestic sprite (creature), sprites or nature sprites. Origins and comparative folklore Etymology The etymology of ' ...
.Darlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 135.


Description


Insect

The female is about long. Parts of the abdomen and legs are yellow-red, while the rest of the body is black. The male is black and lacks the hypopygium structure which clearly identifies the species in the female. Its legs are bicoloured yellow and has a body length of about .


Gall

Some insects create their own microhabitats by forming a plant structure called a
gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external tissues of plants. Plant galls are abnormal outgrowths of plant tissues, similar to benign tumors or war ...
, made up of plant tissue, but controlled by the insect. A gall acts as both a habitat and food source for the maker of the gall. The interior of a bedeguar gall is formed from the bud, and is composed of edible nutritious and structural tissues. Some galls act as "physiologic sinks", concentrating resources in the gall from the surrounding plant parts. Galls may also provide the insect with some physical protection from predators. The bedeguar gall is surrounded by a dense mass of sticky branched filaments. This structure gives the appearance of a ball of moss, and its filaments are often brightly colored, being at their best around September; starting off green and then passing through pink and crimson to reddish brown. A large specimen can be up to in width. The larvae develop and then overwinter as pupae in the now brown and dry-looking structure, emerging in May.Darlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 133. The unilarval chambers are set in a woody core which persists after the filaments have worn off.Stubbs, F. B. Edit. (1986) ''Provisional Keys to British Plant Galls''. Pub. Brit Plant Gall Soc. . P. 56. The bedeguar may also develop on ''Rosa rubiginosa'', ''R. dumalis'', or ''R. rubrifolia''. The gall induced by ''D. mayri'' differs in being more sparsely covered in short, unbranched filaments and the galls usually develop on the twigs.


Lifecycle

A week after the egg has been laid, the larva hatches and begins to feed on the leaf bud tissue. This activity stimulates (in a way not yet understood) the development by the host plant of enlarged 'nutritive' cells in the area around the growing larva. These are fed on by the larva and are continually replaced by new cells. Further concentric layers of tissues develop around the core nutritive tissue and come to form the structure known as the bedeguar, complete with the outermost and characteristic fibrous outgrowths that give the gall its alternative name of Robin's pincushion. As the larva feeds and grows within this gall, it probably undergoes five larval instar stages (the growth stages between moults). The final instar stage is reached by late October. The larva ceases feeding. It now passes into the prepupal stage, in which form it overwinters inside the gall. In the following February or March, the prepupa undergoes a final moult and becomes a pupa. Through the thin, transparent skin of the pupa, it is possible to see the fully formed antennae, legs, wings and body segments of the adult wasp. The adults begin to emerge from the old galls, which are still attached to the rose, in May. Emergences may continue through to August. As stated earlier, the adult wasps which start to emerge from the rose bedeguar will be mostly female, and these females will go on to lay eggs through parthenogenesis. No
alternation of generations Alternation of generations (also known as metagenesis or heterogenesis) is the predominant type of life cycle in plants and algae. In plants both phases are multicellular: the haploid sexual phase – the gametophyte – alternates with a diploi ...
exists in this species. Males are known, but are very rare. One possible reason for this scarcity is the presence of a bacterium in the genus ''
Wolbachia ''Wolbachia'' is a genus of gram-negative bacteria infecting many species of arthropods and filarial nematodes. The symbiotic relationship ranges from parasitism to obligate mutualism. It is one of the most common parasitic microbes of arthrop ...
'', which is
endosymbiotic An endosymbiont or endobiont is an organism that lives within the body or cells of another organism. Typically the two organisms are in a mutualistic relationship. Examples are nitrogen-fixing bacteria (called rhizobia), which live in the root ...
in the females'
gametes A gamete ( ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. The name gamete was introduced by the Ge ...
. A female infected with ''Wolbachia'' produces only
diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...
eggs, when in the cells of the ovaries presumably cause the fusion of the
pronuclei A pronucleus (: pronuclei) denotes the Cell nucleus, nucleus found in either a sperm or egg cell during the process of Fertilisation, fertilization. The Spermatozoon, sperm cell undergoes a transformation into a pronucleus after entering the egg ...
, which leads to entirely female progeny. When the females were treated with
antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...
, they were then able to produce normal male and female eggs.


Predators, inquilines, parasites, hyperparasites and fungi

Mature galls are sometimes broken open by vertebrate predators to recover the larvae or pupae. The large size of the emergence holes of the individual cells sometimes suggests predation by birds or small mammals has taken place. The bedeguar is a good example of a complex community of insects. The cynipid wasp '' Periclistus brandtii'' is an
inquiline In zoology, an inquiline (from Latin ''inquilinus'', "lodger" or "tenant") is an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms, such as insects, may live in the ...
that lives harmlessly within the bedeguar gall and like ''Diplolepis rosae'' itself, is often parasitised by insects referred to as
parasitoids In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...
or even by hyperparasitoids in some cases. The gall-wasp ''Periclistus brandtii'' causes no gall itself, but deposits its eggs in the bedeguar tissues on which the larvae feed. In turn, these larvae may be parasitised by a eurytomid wasp, '' Eurytoma rosae'', which works its way from one inquiline's cell to the next. The parasitoid
ichneumon Ichneumon may refer to: * ''Ichneumon'' (genus), a genus of wasps * ''Ichneumon'', species of wasps in the family Ichneumonidae * Ichneumon, an alternative name for the Egyptian mongoose * Ichneumon (medieval zoology) In medieval literature, th ...
'' Orthopelma mediator'' lays its eggs directly into larvae of ''D. rosae'', killing them. The wasps '' Eurytoma rosae'' and '' Glyphomerus stigma'' can attack both the larvae of ''D. rosae'' and of the inquiline ''P. brandtii''. These parasitoids may in turn be attacked by hyperparasitoids such as '' Caenacis inflexa'' and '' Pteromalus bedeguaris''. The mossy and sticky filaments of the gall are clearly ineffective in preventing the entry of inquilines, predators, parasitoids and hyperparasitoids.Darlington, Arnold (1975) ''The Pocket Encyclopaedia of Plant Galls in Colour.'' Pub. Blandford Press. Poole. . P. 134 - 135. The tissues of the bedeguar gall are frequently attacked by the parasitic fungus '' Phragmidium subcorticum'', more so than the other parts of the host rose plant.


Infestations

The galls occur more commonly on plants under stress, i.e. very dry conditions, waterlogging or hedge cutting, whereas vigorously growing plants are less commonly found to have galls. Whether the vigorous plant suppresses gall formation or is avoided by the wasp in favor of easier targets is unknown. Young and damaged plants tend to produce larger and more numerous galls than old and intact ones. In the latter, many eggs are laid, but the number of galls formed is relatively few. The relative number of parasitoids decreases with increasing gall volume. And the closer the gall is to the ground, the greater the total number of adults that emerge. Thus, it seems more effective for a female ''D. rosae'' to induce larger galls on lower branches of the shrubs to increase the survival probability of the offspring. The distances from margins of shrubs, however, affects neither the parasitoid ratio of galls nor the volume of the galls. Removing and destroying galls before they dry and the wasps emerge may help to reduce the infestation. While fairly large, and sometimes present in quite large numbers on scrub specimens, they cause no measurable harm.


Medicinal uses

Dried and powdered, the gall was used to treat
colic Colic or cholic () is a form of pain that starts and stops abruptly. It occurs due to muscular contractions of a hollow tube (small and large intestine, gall bladder, ureter, etc.) in an attempt to relieve an obstruction by forcing content ou ...
, as a
diuretic A diuretic () is any substance that promotes diuresis, the increased production of urine. This includes forced diuresis. A diuretic tablet is sometimes colloquially called a water tablet. There are several categories of diuretics. All diuretics ...
, and as a remedy against toothache; the ashes mixed with honey and applied to the scalp were thought to prevent baldness. It was also valued as an
astringent An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin '' adstringere'', which means "to bind fast". Astringency, the dry, puckering or numbing mouthfeel caused by t ...
and for its ability to control fluid loss; placed beneath a pillow, it was thought to induce sleep.


References


External links


Rose Bedegaur or Robin's Pincushion video

Video footage of Scottish galls
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{{Taxonbar, from=Q1457797 Cynipidae Gall-inducing insects Hymenoptera of Europe Wasps described in 1758 Taxa named by Carl Linnaeus Puck (folklore)